This invention relates to new catalytic dinitrogen and dihydrogen complexes of a transition metal and to a method for preparation of the complexes.
In recent years, dinitrogen complexes of certain transition metal have been prepared by (1) reacting a coordination, complex of the transition metal with molecular nitrogen in the presence of reducing agent, (2) reacting a hydride of transition metal in lower oxidation state with molecular nitrogen or (3) displacing a weaker ligand in a coordination complex of the transition metal with molecular nitrogen. See, for example, Allen, "Developments in Inorganic Models of N.sub.2 Fixation," Bioinorganic Chemistry, Advances in Chemistry Series, 100, 79(1971) and Allen et al., Chemical Reviews, 73, 11(1973). Such complexes have been described as useful in the fixation of nitrogen. See, for example, Van Tamelen, "Fixation of Molecular Nitrogen under Mild Conditions," Bioinorganic Chemistry, Advances in Chemistry Series, 100, 95(1971).
Heretofore, however, it has not been recognized that molecular nitrogen or molecular hydrogen will react in the absence of a reducing agent with higher oxidation state transition metal compound containing no coordinate covalent bonds to form a dinitrogen or dihydrogen complex of the transition metal.